1. Field of Invention
The invention relates to a method and a device of starting an internal combustion engine.
2. Description of Related Art
There is proposed a method of starting an internal combustion engine of direct injection type where fuel is directly injected into cylinders using energy generated by combustion within the cylinder in expansion stroke upon start of the engine in JP-A-2002-4985 (Related Art No. 1). In the disclosed method, success or failure in starting the engine is estimated on the basis of the engine speed after starting the combustion. If failure in starting the engine is estimated, the starter motor is activated so as to compensate for the energy required for starting the engine. Likewise JP-A-2000-4929 (Related art No. 2) discloses the technology in which the fuel is injected into the cylinder in the expansion stroke when an engine operation is stopped, and ignition is performed after sufficient vaporization of the fuel followed by the passage of a preset delay time. The list of the related art of the invention is described as below:
Related art No. 1:JP-A-2002-4985;Related art No. 2:JP-A-2000-4929;Related art No. 3:JP-A-11-159374; andRelated art No. 4:JP-A-7-119594.
In the aforementioned cases, sufficiency of the energy for starting the engine cannot be preliminarily estimated but determined on the basis of success/failure in starting the engine after performing combustion in the cylinder. The required energy to be compensated by the starter motor activated upon failure of starting the engine cannot be preliminarily controlled as well. Therefore, it is difficult for the aforementioned cases to estimate the kinetic energy required for starting the engine preliminarily before performing the combustion. It is likely to cause insufficiency/excess of the kinetic energy supplied by the combustion or the starter motor with respect to the required kinetic energy for starting the engine. This may result in the start-up failure or over-speed of the internal combustion engine.